You don't have to shop at Harrods any more to dine like a millionaire.

Lidl is selling 100g pots of caviar for just £1.49 – making the delicacy cheaper than a Big Mac.

The budget chain's product is capelin caviar, which is highly prized in Japan, although gourmets do not put it in the same class as the finest Golden Almas caviar.

Sales for the supermarket's Deluxe range have risen by 200 per cent in the last two years

But then it doesn't come with the same price tag of £840 for a measly 30g. Even the cheapest caviar at Fortnum and Mason comes in at £80 for 30g, with prices ranging all the way up to £350 for 200g.

Meanwhile at the likes of Lidl and Aldi, quail, goose and Grand Cru champagne are joining caviar on the shelves as affordable treats for 'Middle Britain' families putting aside their prejudices and looking to stretch their food budgets.

Traditionally, caviar refers to the salted eggs of sturgeon. But now it is an endangered species, the eggs of other fish such as salmon, paddlefish, whitefish and lumpfish can be used if the name is on the packaging.

Lidl's version uses capelin – a small forage fish found in the Atlantic and Arctic oceans.

A Lidl spokesman said they achieve their low price because they produce it on such a large scale.

It was introduced in stores in November 2010 and in the past three weeks the chain has seen a 171 per cent increase in sales compared to last year.

Many stores have had to re-order it to meet customer demand. Budget banquet offerings from Aldi include a whole fresh British goose, typically weighing 4.5kg, for £34.99, while there are quails at £4.99 for four, and venison steaks at £6.99 for 400g.

The Deluxe range at Lidl includes a 1.5kg three bird roast at £9.99. Four quails are £5.99, a pack of venison loin steaks is £9.99 and a frozen goose is a modest £19.99.

It is selling lobster at £5.99 for a 350g pack and 12 large scallops for £3.99.

The growth of the German-owned chains is posing a real threat to Tesco, Asda, Sainsbury's and Morrisons. BMWs and Audis fill their car parks while their products have won a host of taste and quality prizes.

Aldi has seen an 18 per cent increase in shoppers from the wealthiest A and B social classes.

They will be snapping up the chain's Grand Cru Champagne for £22.99, which is a saving of 54 per cent on the usual £49.99 market price.

There is also a Grand Cru Classé 2004 Margaux for £22.99, which is down from a usual £43.82, and a 30 Year Old Tawny Port for £37.99, which is less than half the usual market price of £79.95.

Lidl has seen a 200 per cent increase in sales of its Deluxe range products in the past two years.

Spokesman Georgina Hall said: 'The range allows you to enjoy an aspirational lifestyle without forking out when it comes to cost.' Feed your family on £50 a week